Centralized traffic controlling system for railroads



'r. J. JUDGE 2,145,795

CENTRALIZED TRAFFIC CONTROLLING SYSTEM FOR RAILROADS Jan. 31, 1 939.

2 Sheets-Sheet l Filed Aug. 27, 193

ATTORNEY T. J; JUDGE 2,145,795

GENTRALIZED TRAFFIC CONTROLLING SYSTEM FOR RAILROADS Jan. 31, 1939.

Filed Aug. 27, 1954 '2 Sheets-Sheet 2 E vsmo; I

ATTORNEY Patented Jan. 31, 1939 PATENT OFFICE CENTRALIZED TRAFFICCONTROLLING SYSTEM FOR RAILROADS Thomas J. Judge, Rochester, N. Y.,assignor to General Railway Signal Company, Rochester, N

Application August 27, 1934, Serial No. 741,626

11 Claims.

This invention relates to centralized traific controlling system forrailroads and it more particularly pertains to a system of the non-codedor direct control type as distinguished from aselector.

type system. It is proposed in accordance with the present invention toprovide means for, controlling a remote power operated track switch byselecting I the polarity of energy applied at the control oflice to onelinecircuit and to control the movement of tra'fiic over this switch byselecting the polarity of energy applied to a second line circuit. It isalso proposed-to provide a means for indicating over 'these rsame twoline circuits the response of the track switch to thetransmittedcontrol, the condition'ofthe traflic such as a signal clearor stop condition, the particular direction of traflic set up when asignal is clear and also the particular position and locked or unlockedcondition of the track switch. Furthermore, it is proposed to indicateover these same line circuits the presence of a "train in the tracksection as well as to indicate the locked and unlocked conditions of theswitch control circuits.

It 'is'further proposed to provide such interlocking of the circuits inthe communication of "controls and indications that the transmission ofconflicting controls'is prevented while the system retains sufiicientoperating flexibility to permit efiicient governing of trafiicmovements.

Other objects, purposes and characteristic fea- "tures of the inventionwillappear as the descripftion thereof progresses. During thedescription reference will be made to the accompanying drawings whichillustrate in a diagrammatic and conventional manner one specificembodiment of the present invention which is susceptible of considerablemodification .in practice, depending on the ty-pe of control requiredand the character and number of indications desired in the particular 7application.

' In the accompanying drawings a complete communicating system is shownfor transmitting controls and indications between a typical outlyingfield station and the controloffice which is associatedwith thisstation. It will be understood that in an actual installation of thissystem separate control circuits are required for each station,

these circuits comprising a pair of control line w'iresand a-comrnonreturn wire. These line wires are identified by reference characters WZ.GK. whichv indicate the switch control and the "signal indicating wireand GZWK which indi- Wire C serves as a common return for the abovementioned separate line conductors and it will be understood that thiscommon return may also be used in connection with other circuits whendesired.

It is contemplated that a track diagram corresponding to the associatedtypical track section to which this invention isapplied will be providedin the control ofiice but for the sake of simplicity in the drawingsthis'miniature track diagram has been omitted. It will be understood,however, that the indicating lights shown in the left hand portion ofFig. 1 will be so associated with the track diagram that the operator isreadily advised as to the conditions of the track switch and theassociated signals at the track section with which these lights areassociated.

Fig. 1 indicates in a diagrammatic and conventional manner the circuitarrangement at the control oflice.

Fig. 2 illustrates in a diagrammatic and conventional manner the circuitarrangement at a typical field station.

Referring to Fig. l, a signal control lever SGL is employed to set upthe controls for way-side signals governing trafiic over the trackswitch of 25 Fig. 2. This lever is operable to three positions, namely,right, stop and left indicated in Fig. l by the reference characters R,S and L respectively. Suitable contacts are indicated as being closedwhen lever SGL is in either of its extreme oper- 30 ated positions, withthese contacts being opened when the lever is in its center or stopposition.

A switch control lever SML is operable to either of two positions forsetting up controls for the switch machine employed, to position thetrack switch in either its normal or reverse position. The two positionsto which lever SML can be operated are normal and reverse as indicatedby reference characters N and R respectively. The contacts of the switchmachine lever are preferably of the snap action'type so that they willbe rapidly switched from one position to the other irrespective of thespeed of operation of the lever which controls these contacts.

Track occupancy lamp TK is shown, which is for the purpose of indicatingthe occupancy and unoccupancy of the track section illustrated in Fig.2. Normal and reverse switch indicating lamps NWK and RWK, indicate thatthe track switch is in its normal and its reverse locked positionsrespectively, by the illumination of the respective lamp. When neitherlamp is illuminated this is an indication that the switch is in itsunlocked or mid-stroke position.

Lock lamp LK is lighted to indicate that the Relay WIP is the switchposition indicating relay and relay WZP is a repeater of relay WIP.Relay LIP provides the electric lock equivalent feature which will bedescribed later in the description. Relay LP in the office and relay WZat the station are of the retained neutral, polar type and they servethe purpose of transferring the use of line conductor WZ-GK from switchindication to signal control. These two relays are indicated as being ofthe retained neutral type by the shaded portion of the relay winding.Such a relay maybe of any well known type, one example of which isindicated in the patent to F. C. Larson, No. 1,852,210 issued April 5,1932.

Relays G12 and GZZ are the signal control relays. Relay GIP is thesignal indicating relay. It will be understood that those relays whichhave a solid base line are of the slow acting type.

Referring to Fig. 2, relay WZ repeats the switch control as receivedover the line conductor WZGK and also functions as a transfer relay asabove pointed. out. Relay WR is the relay which controls the switchmachine circuit. Relays NCR and RCR are the normal and reversecorrespondence relays respectively, controlled by relay WR and theswitch repeating relay WP to indicate when the switch control circuitsare in correspondence with the position of the switch machine.

Suitable way-side signals I, IA, 2 and 2A are indicated in theconventional manner as governing trafiic movements over the track switchTS. These signals are selectively cleared to govern traific by means ofassociated signal relays iG, IAG, 2G and ZAG. These signal relays areselected by the position of the signal control relay GZ in accordancewith the proper position of the signal control relay GZ in accordancewith the proper position of the track switch as indicated by thecorresponding relay contacts which are included in these signal relaycircuits.

Associated with the signal relays is a lock relay L which is normallyenergized and is deenergized whenever the signal control relay GZ isenergized, the track relay T is de-energized or any one of the signalclearing relays is energized. The relays RM and LM are the conventionalright and left direction repeating relays arranged in the localsignalling circuits to be normally energized whenever their associatedsignals are at stop but to be de-energized whenever the associatedsignals display clear indications. Relay T is the conventionallyarranged track relay associated with the normally energized section oftrack.

In pointing out the circuits throughout the description of the operationof the present invention, and will be considered opposite terminals of alocal source of energy at the control oifice and also of a similarsource of energy at the field station. (3+) and (B) will be consideredopposite terminals of a source of energy at the control oflice and alsoof a similar source of energy located at the field station, each havinga center tap (CN) connected to the common return conductor C.

It is believed that further description of the present invention willbest be understood by considering the operation under certaincharacteristic or typical conditions.

Operation In the accompanying drawings the track switch TS is shown inits normal position for routing traflic straight through on the maintrack in accordance with the normal position N of the switch controllever SML. Normal switch indicating lamp NWK is lighted to indicate thatthe switch is in correspondence with the switch machine lever. the tracksection are shown at stop as indicated by relays lG, IAG, 2G and 2AG allnormally deenergized; This is in accordance with the center or stopposition of signal lever SGL in the control office and the illuminationof lamp GK indicates to the operator that all signals are at stop.

Normal conditions.With the detector track section associated with trackswitch TS unoccupied by a train, with the control levers SML and SGL inthe positions shown and with the track switch in its normal position asshown, the various devices relays and circuits assume positions andconditions of energization as illustrated.

Track relay T is normally energized in the usual manner. With the switchmachine in its normal position, relay WP has its neutral contact pickedup and its polar contact positioned to the left over the usual circuits.

With all signals at stop, relays HG, IAG, 2G and ZAG are de-energizedwhich establishes a circuit for energizing relay RM extending from backcontact It'll of relay HAG, back contact ID! of relay IG and winding ofrelay RM, to Relay LM is normally energized over a circuit extendingfrom back contact H32 of relay ZAG, back contact I03 of relay 2G andwinding of relay LM to A circuit is closed for energizing relay Lextending from back contact Hi4 of relay ZAG, back contact I05, of relay2G, back contact )6 of relay. IAG, back contact I91 of relay IG, backcontact I08 of relay GZ, winding of relay L and front contact I09 ofrelay T, to

A circuit is closed for normally energizing relay NCR extending fromfront contact ill of relay WP, contact III of relay WP in its left handposition, winding of relay NCR, contact N2 of relay WR in its right handposition and front contact H3 of relay WR, to

A circuit is closed for energizing relay WR extending from (3+), contactE22 of relay WZ in its right hand position, front contact E23 of relayWZ, front contact i2 5 of relay L and winding of relay WR, to (CN).

A circuit is closed for energizing relay LP and positioning its polarcontacts to the left (normal) and for energizing relay WZ andpositioning its polar contact to the right (normal) extending from (B)switch machine lever contact it in its upper position, front contact Hof relay LIP, back contact 12 of relay GZZ, winding of relay LP, backcontact I 3 of relay GIZ, conductor WZGK, front contact H4 of relay RM,front contact H5 of relay LM, winding of relay WZ and front contact H6of relay L, to (CN).

An auxiliary circuit is provided for the WZ GK line circuit through backcontacts M!) and [41 of relays RCR and NCR respectively and front All'ofthe signals associated with.

the switch.

A circuit is closed for energizing relay WIP and positioning its polarcontacts to the left '(normal) which extends from (B+), front contactIll of relay NCR, front contact II8 of relay WZ, front contact II9 ofrelay T, conductor winding of relay WIP, to (CN).

Relay W2P is energized over a circuit extending I from front contact I5of. relay WIP and winding of relay W2P, to Lamp NWK is normally lightedover a circuit extending from a front contact I6 of relay WIP, contactI! of relay WIP in its left hand position, lamp ,NWK and contact I 8 oflever SML in its upper position, to (B). A circuit is closed forlighting lamp GK which extends from back contact I9 of relay GIP andlamp GK, to

- 1 Relay LIP is energized over a circuit extending from (B+), frontcontact 20 of relay LP, back contact 2I-of relay GIZ, winding ofrelay'LIP,

contact 22 of relay WIP in its left hand position and contact 23'oflever SML in its upper position, to (ON). Operation of track switch-Itwill be assumed that the operator desires to reverse trackeswitch TSto'route traflic onto the passing siding and for accomplishingthispurpose lever SML is ,op-

: erated to its lower position The polarity applied to line conductorWZ-GK is thereby quickly reversed by the switching of contact III oflever SML, This reversal inv polarity is ineffective to drop the.neutral contacts of relays LP and WZ '7 but the polar contacts of theserelays are operated to positions opposite from that indicated in thedrawings.

-A circuit is now closed for positioning the polar contacts of relay WRto the left which extends from (B-), contact I22 of relay WZ in.

I itsleft h'and dotted position, front contact I23 of relay WZ, frontcontact I24 of relay L and winding of relay WR to (CN). The switching ofcontact I25 of relay WR operates the switch machine for placing thetrack switch in itsre-' verse position.

With the track switch in its unlocked position relay WP is de-energizedwhich opens the above described circuit of relay NCR at front conisde-energized. 'The de-energization of both lamps NWK and RWK is anindication to the operator that the switch is unlocked.

When the switch reaches its reverse locked position a circuit is closedfor energizing relay RCR j extending from front contact III) of relay;WP, contact II I of relay WP in its righthand V dotted position,winding of relay RCR, contact I I2 of relay WR in its left hand dottedposition and frontcontact II3 of relay WR, to

'A circuit is now closed for energizing relay WIP "and actuating itspolar contacts to the right whichextends from (B), front contact I26 ofrelay RCR, back contact II! of relay NCR, front 'contact N8 of relay WZ,front contact II9 of'relay T, conductor GZ.WK front contact I4 of relayLP and winding of relay WIP, to (CN) A circuit is now closed forlighting lamp RWK as an indication to the operator that the switch is inits reverse lockedposition, which circuit extends from front contact I6of relay WIP, contact I! of relay WIP in its right hand dotted position,lamp RWK and contact I8 of lever SML in its lower position, to (B).

The operation of contact 23 of lever SML from its upper to its lowerposition does not de-energize relay LIP because of a circuit closed withcontact 23in its lower position which extends from (B+), front contact20 of relay LP, back contact 2I of relay GIZ, winding of relay LIP,contact 22 of relay WIP in its right hand dotted position and contact 23of lever SML in its lower position, to (CN) After the switching ofcontact 23 and before contact 22 of relay WIP is actuated to the rightthe above described circuit extends through front contact 24 of relayLIP, which contact bridges contact 22.

It will be understood that suitable approach locking means is providedin the control circuits for the switch machine SM but in order tosimplify the present disclosure such locking means have been omittedfrom the drawings.

The operation involved in operating the track switch from its reverselocked position to its normal locked position is merely the inverse ofthe operation already described and will not be specifically pointedout. Such operation may be understood by analogy, considering that leverSML returned to the upper (normal) position reverses the polarity. uponline conductor WZGK and reverses the polar contacts of relays LP and WZwithout dropping their neutral contacts. Relay LIP is maintainedenergized during this operation in a manner similar to that previouslydescribed.

Signal Control.It will now be assumed that the operator desires to allowa train movement from the main track to the right onto the divergingtrack over the track switch in its reverse position. The signal controllever SGL is moved to its upper (right) position which closes a circuitfor energizing relay GIZ extending from (B+),

lie-energizes relay LIP for providing the electriclock equivalent whichwill be described in detail later.

The opening of back contact I3 of relay GIZ opens the energizing circuitof relays LP and WZ. The circuit through thefront point of contact I3 isnot completed to the winding of relay LP because contact 26 of relay LPis in its right hand dotted position which opens the later to bedescribed substitute circuit for relay LP. Relay LP therefore drops itsneutral contacts and it will be recalled that its polar contacts are intheir right hand dotted positions due to the reverse switch controlwhich was transmitted over conductor WZ-GK.

The de-energization of relay LP opens front contact I4 whichde-energizes relay WIP. With relays, LP and WZ de-energized a circuit isclosed for energizing relays G2Z and GZ in series which extends from(B+), contact 21 of lever SGL in its upper dotted position, winding ofrelay G2Z,

back contact I4 of relay LP, conductor GZWK,

front contact H9 of relay T, back contact H8 of relay WZ, front contactI21 of relay RCR. and winding of relay GZ, to (CN). This is effective toposition the polar contacts of relay GZ to the left (right signal). Inthe event that correspondence relay NCR is picked up when relay WZ isde-energized the circuit for relay GZ extends through front contact I41of relay NOR. instead of contact I21 of relay RCR.

The opening of back contact I2 of relay GZZ opens the switch controlcircuit including the winding of relay LP. The opening of front contactI4 of relay LP opened the energizing circuit of relay WIP abovedescribed but a stick circuit for this relay is completed from (B),contact 23 of relay WIP in its right hand dotted position, front contact29 of relay G2Z and winding of relay W IP, to (ON) for maintaining relayWIP in its last operated position. This prevents the dropping of relayWZP because front contact I5 of relay W HP is not opened.

Signal EA is cleared by the picking up of signal relay IAG over acircuit extending from front contact I28 of relay T, front contact I29of relay GZ, contact I30 of relay GZ in its left hand position, frontcontact I3I of relay RCR and winding of relay IAG, to Contact E32 ofrelay IAG changes signal IA from a stop to a clear indication in thewell known manner.

The opening of back contact I06 of relay IAG de-energizes lock relay Lwhich further opens the energizing circuit of relay WZ at contact H6.The dropping of contact I24 of relay L provides the electric biascontrol for relay WR. so that this relay is maintained in its lastenergized position over a circuit extending from (B), contact I33 ofrelay WR in its left hand dotted position, front contact I34 of relayWR, back contact I24 of relay L and winding of relay WR, to (ON) Theopening of back contact I00 of relay IAG de-energized relay RM. Thedropping of relay RM closes a circuit for energizing relay GIP whichextends from (B+), back contact N4 of relay RM, conductor WZ-GK, frontcontact I3 of relay GIZ, front contact 30 of relay WZP, back contact 3iof relay LP and Winding of relay GIP, to (ON) Relay GIP picks up itsneutral contacts and actuates its polar contacts to the left. A circuitis now closed for lighting lamp RGK extending from front contact I9 ofrelay GIP, contact 32 of relay (HP, in its left hand position and lampRGK, to The opening of back contact i9 de-energizes the circuit of lampGK and the lighting of lamp RGK is an indication to the operator that asignal at the track section is clear for traffic to proceed to theright.

The manner in which a signal may be cleared for traffic to the left isobvious from the foregoing description, since the operation of lever SGLto its lower position applies (B) potential to the upper winding ofrelay GIZ for energizing this relay as before and for applying (B)potential to conductor GZ-WK through the windings of relays GZZ and GZ,which energizes these relays as before but positions the polar contactof relay GZ to the right instead of to the left. The above describedcircuit for the signal relay now extends through contact I38 in itsright hand position and front contact I35 of relay RCR to relay 2AG.

The picking up of relay ZAG clears signal 2A by the actuation of contactI36. The opening of back contact I04 de-energizes relay L as before andthe opening of back contact I02 de-energizes relay LM which applies (B)to conductor WZ-GK for positioning relay GIP to the right. This closes acircuit for lamp LGK which extends from front contact I9 of relay GIP,contact 32 of relay GIP in its right hand dotted position and lamp LGK,to

In the event that signal I is to be cleared with track switch TS in itsnormal position, then relay IG is energized over a circuit includingcontact I30 of relay GZ in its left hand (traffic to the right) positionand front contact I31 of relay NCR to the winding of relay IG. Relay NCRwould be picked up under this condition over the circuit previouslydescribed in connection with the normal circuit conditions. Contact I44of relay I G clears signal I.

Signal 2 is cleared by the picking up of contact I38 of relay 2G whenthis relay is energized over a circuit including contact I30 of relay GZin its right hand position and front contact I39 of relay NCR.

Track occupancy.I-Iaving described the manner in which the track switchis controlled from the control office and the signals are governed fortraffic over this switch it will now be assumed that a train enters theillustrated track section thereby drop-ping relay T.

The opening of front contact I03 de-energizes the lock relay circuit sothat the position of the track switch cannot be changed while the tracksection is occupied. It will be understood that the de-energization ofrelay L in response to the clearing of a signal previously describedalso looks the track switch against a change in position as long as asignal is clear.

The opening of front contact I28 of relay T de-energizes the circuit ofthe particular G relay which was energized so that all of these relaysare de-energized for placing all signals at stop.

With all G relays de-energized, relays RM and LM are energized and sincerelay L is de-energized the circuit including line conductor WZGK isde-energized at front contact H3 of relay L. The de-energization of thisline conductor drops relay GI P which is effective to again energizelamp GK at its back contact I9 as an indication that all signals are atstop.

The opening of front contact N9 of relay T obviously de-energizes relayG2Z which inturn de-energizes relay WIP by opening front contact 29.Front contact 33 of relay GIP is open at this time since relay GIP isde-energized as above pointed out.

A circuit is closed for lighting track occupancy lamp TK which extendsfrom (B-]-) back contact 20 of relay LP, back contact 34 of relay WIPand lamp TK, to (B). The opening of contact I5 of relay WIP de-energizesrelay WZP but due to the slow acting characteristics of the latter relaya circuit is momentarily closed for energizing the annunciator ANextending from back contact I5 of relay WIP, front contact 35 of relayWZP, back contact 36 of relay LP and annunciator, to It will be obviousthat when the track becomes unoccupied, relay WIP picks up its contactI5 thereby opening the annunciator circuit before it is closed at frontcontact 35 of relay WZP so that the audible alarm is not given.

As soon as the train leaves the track section,

relay T is energized which returns the system to its normal condition asdetermined by the positions of the control levers SGL and SML and thecircuit of lamp TK will be de-energized by the opening of back contact34 of relay WIP.

It will thus be seen that the signals may be manually put to stop at theremote station by de-energizing conductor GZ-WK for dropping relay GZ atthe station. This conductor is deenergized by contact 21 of lever SGL inits stop position if relay LP is de-en-ergized with back contact I4closed. If relay LP is energized'then relay GZ cannot beenergized overconductor GZ-WK because the windings of relays W IP and GZ both connectto (ON) so that no circuit is made up for current toflow through eitherof these relay windings.

" The purpose of back contacts I20 and IN on relays LM and RM is toprevent the track occupancy indication being displayed at the same 7time a signal clear indication is displayed. More l specifically, thetrack occupancy indication is 1 sent'in when contact N9 of relay T isopened and the signal clear indication is sent in by closing backcontact I I4 or H5 of relay RM 01 relay LM. Therefore, opening frontcontact H9 will not send in a track occupancy indication as long as thiscontact is ,bridged'by either contact 7 I20 or 12! being closed due torelay LM or RM being'de-energized to transmit a signal clear indication.Thus, the track occupancy indication will not be displayed at the sametime a signal clear indication is displayed.

-Electric lock equivalent-In the event that v lever SML is operated to aposition out of correspondence with the contacts of relay WIP while theswitch control circuit including relay LP is de-energized, then leverSML must be returned to a .position corresponding with the positions 7of the contacts of relay WIP in order to effect 30 control conductorWZ-GK. This is because the the" control oftheswitch machine, even uponsubsequent energization of relay LP and the dropping of relay LP.de-energizes relay LIP so that this relay cannot be again picked up, be-

cause of open front contact 24, until the switch machine lever contact23 is in a position which corresponds to the position of contact 22 ofrelay-WIP. In other words, as soon as the signal lever is operated to aclear position for pick-- ing up relay GIZ, the opening of back contact2| prevents a change in switch control until the 7 switch control leveris returned to the position which was last effective.

"With relay LIP de-energized, a circuit is closed for lighting lamp LKas an indication that the switch control circuits are locked, whichcircuit 'extends'from back contact 40 of relayLlP and lamp. LK, to Also,with relay LIP de-i-energized a circuit is closed for energizing Iexample, if this conductor is energized from (3+) through contact In oflever SML in its conductor WZ-GK with the polarity with which thisconductor was last energized by the operation of switch machine leverSML. For

flower (reverse) dotted position, relay LP will actuate its polarcontacts to the right (reverse) and upon the dropping of contact ll ofrelay Y LIP this polarity of energization is maintained by a circuitincluding contact 41 of relay LP in its right hand dotted position.

I be made even momentarily when the position of the switch lever ischanged. Thistransfer must notbe made after the switch lever has beenoperated until the switch movement'has been completed even though thesignal lever has been operated in the meantime.

More specifically, it will be assumed that the switch leveris operatedand that the signal lever is qu ck yop e esl'ih eefi rr T e p a ion ofThe converse is true with lever SML in its upper po-- lever SGLenergizes relay GI Z which opens conductor WZ-GK at back contact l3 butthis circuit is not de-energized because of a circuit extendingthroughfront contact l3 of relay GIZ, front contact 30 of relay W2P, frontcontact 3| of relay LP, contact 31 of relay WIP in its left handposition (normal), contact 26 of relay LP in its right hand dottedposition (reverse) and through the winding of relay LP, to (3+) atcontact ll) of lever SML over the previously described circuit. This isof course assuming that lever SML is operated from normal to reverse andthat relay LP responds to close the above described circuit before relayWIP is de-energized.

When the switch starts its movement, relay WIP becomes de-energizedbecause both correspondence relays NCR and RCR will be de-energized toopen conductor GZWK at contacts Ill and I26. The dropping of relay WIPde-energizes relay W2P and the above described circuit through frontcontact l3 of relay GIZ is transferred by way of back contact 30 ofrelay WZP to the winding of relay LP for maintaining this relayenergized.

When the switch has completed its movement relay WI P is energized toits reverse position and relay W2P is picked up over the local circuitthrough front contact l5. This opens the above described circuit atcontact 37 in its right hand dotted position because contact 26 of relayLP is in its right hand dotted position. Therefore relays LP and WZ areboth de-energized thus effecting the transfer of conductor GZ-WK fromswitch indication to signal control- Current now flows from (B) or (B+)depending upon the position of contact 21, through relay G2Z, backcontact M of relay LP, conductor GZWK, front contact i I9 of relay T,back contact H8 of relay WZ, and front contact I21 of relay RCR to thewinding of relay GZ. Current over this circuit is efiective to energizerelays G2Z and GZ in series. With relay G2Z energized, relay WIP is heldin a position to which it was last operated by the correspondence relayat the field station over a circuit including contact '28 of relay WIP.

The use of relay GIP for indicating the direction of traffic which iscleared by means of its contacts l9 and 32, as previously described,also provides another feature. A retaining (lower) winding is providedfor relay GIZ which serves to hold this relay energized as long as anindication is coming in that a signal is clear even though the signallever is restored to its stop position. For example, if a signal to theright has been cleared relay GIP will have its polar contacts actuatedto the left as previously described. An energizing circuit is nowcompleted for the retaining winding of relay GIZ extending from (3+),contact 38 of relay GIP in its left hand position, front contact 39 ofrelay GIP and lower winding of relay GIZ to (CN). It will be observedthat the energization of this retaining winding is in the same directionas the energization of the upper winding of this relay by lever SGL inits upper (right) clearing position.

This arrangement provides a check that traific direction has beenestablished at the field station in conformity with the position of thesignal lever. If such conformity does not exist current flows throughthe two windings of relays GI Z in opposite directions thustie-energizing the relay. For example, if lever SGL is actuated to itsupper position, the upper winding of relay GIZ is energized from (B+) atcontact 25 of the signal lever.

at the station is established for traffic to proceed to the left, relayGlP will have its polar con-' tact 38 positionedto the right whichenergizes the lower winding of relay GiZ from (B) thus causing relay GIZ to be de-energized. The opening of front contact 53 of relay GlZde-energ-izes relay GIP which in turn de-energizes the lower winding ofrelay GlZ at front contact 39 thus allowing relay GIZ to again pick up.This produces a cycle of operations of relays GI Z and GlP which causesthe sigal indication lamps to flash by the continued switching ofcontact 19 of relay GiP as an indication that conformity does not existbetween the signal lever and the trafiic direction established at thestation.

It will be noted that the dropping of track relay T or correspondencerelay NCR, with the circuits in the condition shown, de-energizesnormally energized relay WIP. It will also be noted that normallyenergized relay LP is de-energized when the track section is occupiedbecause the opening'of front contact I09 of relay T de-energizes relayL. Relay L opens its front contact H6 to de-energize the line conductorin which relay LP is included. Therefore relay LP effects theenergization of the track occupancy lamp TK and the switch positionindicating lamp NWK or RWK when relay WIP is de-energized. In additionto this the switch position indicating lamp circuits are de-energizedwhenever the switch machine lever and relay W! P are not incorrespondence and these lights remain dark when the lever is moveduntil the switch has completed its movement and is in correspondencewith the lever position.

It is to be understood that although only one specific embodiment of theinvention has been disclosed, the principles set forth may be app-liedto various other types of systems. and various complicated track layoutsmay be controlled in a similar manner, since the present disclosure ischosen merely for the sake of simplicity andclearness in describing theinvention.

Having described a traffic controlling system as one specific embodimentof the present inven tion, it is desired to be understood that this formis selected to facilitate in the disclosure of the invention rather thanto limit the number of forms which it may assume and it is to be furtherunderstood that various modifications, adaptations and alterations maybe applied to the specific form shown to meet the requirements ofpractice, without in any manner departing from the spirit or scope ofthe present invention except as limited by the appended claims.

Having described my invention, I now claim:

1. In a railway traffic controlling system, a control office and a fieldstation connected by a first and a second control line wire,switchcentrolling means for controlling a track switch at said stationby energizing said first control line wire at the control ofiice, signalclearing means for clearing a signal at said station by energizing saidsecond control line wire at the control office, switch and signalindicating means at said office, means for initially connecting saidsecond control line wire to said switch indicating means only when saidfirst control line wire is energized, and means for connecting saidfirst control line wire tosaid signal indicating means only when saidfirst control line wire is deenergized.

2. In a railway trafiic controlling system, a control ofiice and a fieldstation: connected by a first and a second control line wire, signalcontrol Ifrelay GIP indicates that the trafiic direction means at saidoffice, means for controlling a track switch at'said station byenergizing said first control line wire at the control office, means forclearing a signal at said station by energizing said second control linewire at the control ofilce, switch and signal indicating devices at saidoflice, means for initially connecting said second control line wire tosaid switch indicating means only when said first control line wire isenergized, means for connecting said first control line wire to saidsignal indicating means only when said first control line. wireisdeenergized, and means at said control ofi'lce for connecting saidsecond line wire to said signal control means only when said firstcontrol line wire is deenergized.

3. In a centralized traflic controlling system for railroads, a controlofiice, a field station, a track switch at said field station, apower-operated switch machine for operating said track switch, signalsfor governing trafiic oversaid track switch,

a switch control relay at said field station for governing the operationof said switch machine,

a signal control relay at said field station for governing the operationof said signals, a. switch control lever and a signal control lever atsaid control ofiic'e, a'switch indicating relay and a: signal indicatingrelay at the control ofiice, one control line wire normally connectingsaid switch control lever and said switch control relay, another controlline wire normally connecting said switch indicating relay and contactscontrolled by said track switch, means effective when said signalcontrol lever is in one position and responsive to the deenergization ofsaid one control line wire to connect said signal control lever andsignal control relay by said another control line wire, and meanseffective when said signal lever is in one position and responsive tothe energization of said another control line wire to connect saidsignal indicating relay and contacts operated by said signals over saidone control line wire.

4. In a centralized trafiic controlling system for railroads, a controloffice, a field station, a track switch at said field station, apower-operated switch machine for operating said track switch, signalsfor governing trafiic over said track switch, a switch control relay atsaid field station for governing the operation of said switch machine, asignal control relay at said field station for governing the operationof said signals, a switch control lever and a signal control lever atsaid control ofiice, a switch indicating relay and a signal indicatingrelay at the control ofiice, one control line wire normally connectingsaid switch control lever and said switch control relay, another controlline wire normally connecting said switch indicating relay and contactscontrolled by said track switch, means effective when said signalcontrol lever is in one position and responsive to the deenergization ofsaid one control line wire to connect said signal control lever andsignal control relay by said another control line wire means effectivewhen said signal control lever is in another position and responsive tothe energization of'said another control line wire to connect saidsignal indicating relay and contacts controlled by said signals oversaid one control line wire, a relay for causing the deenergization ofsaid one control line wire, a pick-up circuit for said relay closedwhenever said signal lever is in an operated position, and a holdingcircuit for said relay closed whenever said signal indicating relayindicates the clear condition of said signals.

5. In a centralized trafiic controlling system for railroads; acontrolofiice; a field station; a powerretained-neutral polar type at saidfield station; a switch control lever at said control ofiice; a linerepeating relay of'the retained-neutral-polar type at said controlofi'ice; one control line wire connecting said switch control lever,said switch control relay and said line repeating relay in series, sothat operation of said switch control lever toan opposite positionreverses the polarity of current in said one control line wire to causethe operation of said track switch to an opposite position; an-

-other control line wire connecting said'control oflice and said fieldstation; means including neutral contacts of said switch control andline repeating relays for connecting said another control line wire toone set of devices when said re tained-neutral-polar relays areenergized and for connecting said another control line wire to an-;other set of devices when said relays are deenergized; and means for attimes deenergizing said one control line wire; whereby the reversal ofpolarity in said one control line wire by said switch control lever isinefiective to shift the con- 0 Y nection of said another control linewire from one set of devices to the other but wherebythe deenergizationof said one control line wire by said last named'means effects a shiftof the connection of said another control line wire from one set ofdevices to the other. j 6. In combination, a power-operated trackswitch, a switch control lever for governing the power operation of saidtrack switch, signals for governing traffic over said track switch, asignal control lever'for clearing said signals when operated to aclearing position, a single winding lock relay having a front contactfor allowing said switch control lever to govern said track'switch onlywhen such contact is closed, a pick-up cirquit for said lock relaycapable of being closed only when saidswitch control lever is in aposition corresponding to the actual position to which said track switchwas last'operated, a stick circuitfor said lock relay capable of beingclosed independentlyof the position of said track switch, and means foropening both said pick-upand a stick circuits whenever said signal leveris in a "signal clearing position and so long as any one of saidsignalsis clear.

7. In a railway traific controlling system, a

a control office and a field statio-n connected by a first control linewire and a second control line wire, switch controlling, means forcontrolling a track switch at said station by energizing said firstcontrol line wire at the control oflice, signal clearing means forclearing a signal at said station by energizing said second control linewire at the control office, switch and signal indicating means at saidofiioe, means for initially connecting said second control line wire tosaid switch indicating means only when said first control line wire isenergized, means for connecting said first control line wire to saidsignal indicating means only when said first control line wire isdeenergized; and means controlled by said signal clearing means foreffecting said de-energization of said first control line wire. I

8. In a centralized trafiic controlling system for railroads, a controloflice and a field station connected by a first and a second controlline wire,

a switch control lever and a signal control lever at said ofiice, atrack switch and associated signals at said station, means responsive tothe operation of said switch control lever for controlling the operationof said track switch over of one polarity or the e by a relatively quickchange the operation of said signal control lever for controlling theoperation of said signals over said second control line wire, a relay, acircuit for said relay energized by the operation of said signal leverto a signal clearing position independently of the energized ordeenergized condition of said line wires, contacts controlled by saidrelay for transferring said first line wire from a switch control to asignal indication circuit at said control ofiice, and means fortransmitting signal indications over said first line wire.

9. In combination, a power operated track switch, a switch positionindicating relay controlled in accordance with the position to whichsaid track switch is operated, a switch control lever for governing theoperation of said track switch, signals for governing traflic over saidtrack switch, a signal control lever for clearing said signals whenoperated to a signal clearing position, a single wound lock relay havinga front contact for allowing said switch control lever to govern saidtrack switch only when said contact is closed, a pick up circuit forsaid lock relay capable of being closed only when said switch controllever is in a position corresponding to the'last operated position ofsaid track switch as indicated by said switch position indicating relay,a stick circuit for said lock relay capable of being closedindependently of the position of said track switch, means for openingboth said pick up and said stick circuits whenever said signal lever isin a clearing position and so long as any one of said signals is clearwhereby said lock relay is deenergized, and means visually indicatingwhen said lock relay is deenergized.

10. In combination, a polarized line circuit connecting a control officeand a field station, a retained-neutral-polar relay included in seriesin said polarized line circuit at the control ofiice and another suchretained-neutral-polar relay included in series in said polarized linecircuit at thefield station, means at the control office for energizingsaid polarized line circuit with current other in accordance with theposition of a control lever, a traific controlling device at the fieldstation controlled in accordance with the polarity of current in saidpolarized line circuit as repeated by said another retainedneutral-polarrelay, another line circuit connecting the control ofiice and the fieldstation and including a front neutral contact on each of saidretained-neutral-polar relays for completing such another line circuit,electro-responsive means controlled over said another line circuit,wherein the direction of current flow in said polarized line circuitdoes not interrupt the continuity of said another line circuit.

11. In combination, a first line wire connecting a control ofiice and afield station, a retainedneutral-polar relay at said oifice and at saidstation included in series in said first line wire, means at the controlofiice for determining the direction of current flow in said first linewire, a trafiic controlling device at the field station controlled inaccordance with the direction of current fiow in said first line wire asrepeated by the retained-neutral-polar relay at said field station,another line wire connecting the control oflice and field station, meansincluding front contacts on both said retained-neutral-polar relays forclosing an indication circuit over said another line wire when saidfirst line wire is energized,

means including back contacts on both said. retained-neutral-polarrelays for closing a control circuit over said another line wire onlywhen continued. deenergization of said polarized line Wire is effected,and means for at times effecting continued deenergization of saidpolarized line wire,

whereby a relatively quick change in the direction of current flow insaid first line wire is ineffective to momentarily interrupt saidindication line circuit.

THOMAS J. JUDGE.

